1. Field of the Invention
The invention relates in general to a signal processing method and an electronic device, and more particularly to a signal filtering method and an electronic device.
2. Description of the Related Art
In recent years, the development in mobile technology has brought huge potential to the market of electronic devices. For example, the electronic device, such as personal digital assistants, (PDA), smartphone and touch phone, has become a necessity to people's life.
In order to operate the electronic device, conventional electronic device is equipped with mechanic buttons for the user to operate with. In addition, electronic devices with sensing elements are also available in the market. The sensing element may include a number of capacitive sensors. When the user places his or her finger on the sensing element and applies a pressure thereon, the corresponding capacitive sensor sense variations so that the positions touched by the finger can be identified. Moreover, the moving direction of the finger on the sensing element such as clockwise or anti-clockwise may also be identified by way of continuous sensing. Thus, when the user operates the electronic device, he or she only needs to press or slide on the sensing element with one finger so as to operate the electronic device such as moving the cursor, adjusting the volume or selecting the song.
However, when such sensing element is used, the electronic device may encounter the problem of unstable operation due to the reasons being simply stated hereinbelow. Because the electronic device has complicated circuits, the signals obtained by sensing wheel will be interfered when signals are transmitted between circuits. Furthermore, when the electronic device normally uses high power telecommunication, signal interference will occur and the sensing element will sense a large volume of noises. Also, the electronic device will become unstable when affected by temperature and moisture or when the sensing element senses unexpected signals caused by user's improper operation. Thus, it is an important subject in the industry to enhance the operation stability of the electronic device equipped with the sensing element and thus to enhance the usability for the user.